Fix for Issue #6 Event handler removal fails.

JavaScript/JQuery.hs

@@ -213,6 +213,7 @@ import           Data.JSString as S (pack)
 import           Data.JSString.Text as S (textToJSString)
 import           Data.Text as Text (Text)
 import           Data.Typeable
+import           System.IO (fixIO)
 
 default (JSString)
 
@@ -445,19 +446,21 @@ on a et hs jq = do
   cb <- if hsSynchronous hs
           then Cb.syncCallback1 ContinueAsync (a . Event)
           else Cb.asyncCallback1 (a . Event)
-  jq_on cb et' ds hd sp sip pd jq
-  return (jq_off cb et' ds jq >> Cb.releaseCallback cb)
+  cb' <- jq_on cb et' ds hd sp sip pd jq
+  return (jq_off cb' et' ds jq >> Cb.releaseCallback cb)
     where
       et'                   = textToJSString et
       (pd, sp, sip, ds, hd) = convertHandlerSettings hs
 
 one :: (Event -> IO ()) -> EventType -> HandlerSettings -> JQuery -> IO (IO ())
 one a et hs jq = do
-  cb <- if hsSynchronous hs
-          then Cb.syncCallback1 ContinueAsync (a . Event)
-          else Cb.asyncCallback1 (a . Event)
-  jq_one cb et' ds hd sp sip pd jq
-  return (jq_off cb et' ds jq >> Cb.releaseCallback cb)
+  cb <- fixIO $ \cb ->
+      let a' = \e -> Cb.releaseCallback cb >> a e
+      in if hsSynchronous hs
+            then Cb.syncCallback1 ContinueAsync (a' . Event)
+            else Cb.asyncCallback1  (a' . Event)
+  cb' <- jq_one cb et' ds hd sp sip pd jq
+  return (jq_off cb' et' ds jq >> Cb.releaseCallback cb)
     where
       et'                   = textToJSString et
       (pd, sp, sip, ds, hd) = convertHandlerSettings hs

JavaScript/JQuery/Internal.hs

@@ -163,7 +163,7 @@ foreign import javascript unsafe "$8.on($2, $3, $4, h$jquery_makeListener($1, $5
         -> Bool                   -- ^ stopImmediatePropagation
         -> Bool                   -- ^ preventDefault
         -> JQuery
-        -> IO ()
+        -> IO (Callback a)
 
 foreign import javascript unsafe "$8.one($2, $3, $4, h$jquery_makeListener($1, $5, $6, $7))"
   jq_one :: Callback a             -- ^ callback
@@ -174,7 +174,7 @@ foreign import javascript unsafe "$8.one($2, $3, $4, h$jquery_makeListener($1, $
          -> Bool                   -- ^ stopImmediatePropagation
          -> Bool                   -- ^ preventDefault
          -> JQuery
-         -> IO ()
+         -> IO (Callback a)
 
 foreign import javascript unsafe "$4.off($2,$3,$1)"
   jq_off :: Callback a             -- ^ callback

example/Main.hs

@@ -15,15 +15,15 @@ main = ready $ do
   myCount <- select "<div>0</div>"
   counter <- newIORef (0::Int)
   let getCount = atomicModifyIORef counter (\c -> let c' = c+1 in (c', T.pack $ show c'))
-  click (\_ -> void $ getCount >>= flip (setText . textToJSString) myCount) def myClick
-  select "#counter-area" >>= appendJQuery myClick >>= appendJQuery myCount
+  _ <- click (\_ -> void $ getCount >>= flip (setText . textToJSString) myCount) def myClick
+  _ <- select "#counter-area" >>= appendJQuery myClick >>= appendJQuery myCount
   theBtn <- select "#a-button"
   theMsg <- select "#a-message"
-  click (\e -> do
+  _ <- click (\e -> do
                preventDefault e
                void $ do
-                 setHtml "Clicked!" theMsg
-                 removeClass "btn-primary" theBtn
+                 _ <- setHtml "Clicked!" theMsg
+                 _ <- removeClass "btn-primary" theBtn
                  addClass "btn-success" theBtn
         ) def theBtn
   return ()